This invention relates to balancing devices for use on an engine to eliminate or minimize the reaction moment occurring with change in rotation speed of the engine crankshaft.
In general, when an engine crankshaft is accelerated or ddecelerated, the crankcase, rotatably supporting the crankshaft, is subjected to a rotational moment or torque as a reaction to the change in speed of the crankshaft. Obviously, such reaction moment acts as a rocking moment upon the crankcase and associated support structure and is liable to cause engine oscillation. Particularly, with the case of motorcycles, usually carrying an engine with its crankshaft arranged in the fore and aft direction of the body of the motorcycle, such reaction moment acts on the cycle body to cause lateral oscillation thereof and involves difficulties such as loss of stability in running attitude of the cycle.